I have a 14 month old atoo that won't eat his food. ?

He came to me Only eating pop tarts, formula by a syringe, applesauce and baby cereal. He wont eat any of his seeds I give him or pellets. I have tried soaking them in things to moisten them and still nothing. I have tried to give him everything I eat while I eat, he just throws the food down. I put fresh fruit and veg every day and still nothing. I love him and don't want anything to happen to him. Someone please give me some help.. Thank you